In Reply We thank Miguel et al for their response to our article1 documenting the outcome of children with hypoxic ischemic encephalopathy (HIE) at 18 to 42 months, in which we showed that the cognitive abilities of children with a history of mild HIE were significantly lower than those of healthy control children.

Miguel et al highlight their work,2 which examined inherited differences in the dopamine transporter gene (DAT1) function and their effect on cognitive flexibility measured at 4 to 6 years of age. Polymorphisms in the DAT1 gene have been repeatedly associated with attention deficient disorder.3 In their study,2 healthy children from 2 birth cohorts were divided into those with a high expression–based polygenic risk score (ePRS) and those with a low ePRS. They report that, in these cohorts, DAT1 expression remained stable over time and was associated with regional gray matter density.